Air operated motor



June 26, 1956 w, MOHLER 2,751,839

AIR-OPERATED MOTOR Filed April 5, 1954 2 Sheets-Sheet l INVENTOR. MAL/AMfMw-am ATTOE/VEY June 26, 1956 Filed April 5. 1954 W. F. MOHLERAIR-OPERATED MOTOR 2 Sheets$heet 2 INVENTOR. W/LL/A/v/ F/WQHAEP ATTORNEYAIR-OPERATED MOTOR William F. Mohler, Hermosa Beach, Calif., assignor ofone-third to John Vedder, West Covina, Calif., and one-third to BorgertVedder, Fullerton, Calif.

Application April 5, 1954, Serial No. 420,803

3 Claims. (Cl. 121-157) This invention relates to pumping means anddeals more particularly with a reciprocating air-operated booster pump.

An object of the present invention is to provide novel and improvedself-reversing automatic means that is operated by a continuous flow ofpressure fluid, such as compressed air, said means reciprocating theplunger of a booster pump.

Another object of the invention is to provide air-controlledpump-reciprocating means that embodies novel and smooth-actingvalve-controlled air-flow-reversing means.

Since a reciprocating pump has alternate power and recovery strokes ormovement, it is another object of the invention to automatically use lowpower for the recovery stroke and, thereby, save in the cost ofoperation of such pump.

The invention also has for its objects to provide such means that arepositive in operation, convenient in use, easily installed in a workingposition and easily disconnected therefrom, economical of manufacture,relatively simple, and of general superiority and serviceability.

The invention also comprises novel details of construction and novelcombinations and arrangements of parts, which will more fully appear inthe course of the following description. However, the drawings merelyshow and the following description merely describes, one embodiment ofthe present invention, which is given by way of illustration or exampleonly.

In the drawings, like reference characters designate similar parts inthe several views.

Fig. 1 is a longitudinal sectional view, partly in elevation, of anair-operated reciprocating pump according to the present invention, thesame being shown at the beginning of the power stroke of said pump.

Fig. 2 is a similar view showing the pump at the beginning of itsrecovery stroke.

Fig. 3 is an end view as seen from the right of Figs. 1 and 2.

Figs. 4, and 6 are cross-sectional views as taken on the respectivelines 4-4, 55 and 6-6 of Fig. 1.

The pump that is illustrated embodies, in combination, a positivedisplacement pump 10 having an inlet 11 and an outlet 12 and controlledby a plunger 13, and airoperated motor means 14 to reciprocate saidplunger to etfect an intake of liquid at one pressure in inlet 11 and anoutlet of said liquid at an increase pressure from outlet 12. Thisinvention pertains particularly to the motor means 14.

Said air-operated motor means 14 comprises, generally, a valve body 15,an air cylinder 16 extending from said body and at the end thereof,mounting displacement pump 10, a piston 17 operable in said cylinder 16,a valve pilot and guide element 18 extending from said piston 17 intothe body 15, a pilot shifter valve 19, and an air-piston actuating valve20, said elements 18, 19 and 2% being coaxial and on the axis ofcylinder 16.

The valve body preferably comprises a metal casting formed, at one side,with an inlet port 21 for pressure hired States Patent 6 fluid such ascompressed air and, at the opposite side, with an exhaust port 22. Saidbody is provided with transverse walls 23, 24, 25 and 26 longitudinallyspaced from each other. A common longitudinal bore 27 is provided insaid walls, the same being of a diametral size to slidingly accommodateactuating valve 20. A cored passage 28 communciates the annular space 29between walls 25 and 26 with inlet port 21. A similar annular space 30between walls 23 and 24 communicates with exhaust port 22. As best seenin Fig. 4, a baflie wall 31 is placed in front of said port to obviatedirect escape of air through said port. An annular chamber 32 is definedbetween transverse walls 24 and 25 and an intermediate longitudinalpassage 33 communicates chamber 32 and the inside of air cylinder 16.

The air cylinder 16 is longitudinally defined between body 15 and anopposed cylinder end 34 and circumferentially defined by a cylinder tube35. Said body 15 and end 34 are connected to said tube in a similarmanner. As shown, a set of bolts 36 extends through said body and saidend and the same are threadedly engaged with a ring 37 within thecylinder and held against endwise displacement by a snap ring 38 in aninternal groove in said cylinder tube. Since said body 15 and end 34abut the opposite end of cylinder tube 35, the heads of said boltseffectively lock the assembly of body 15 and cylinder 16.

The piston 17 reciprocates between body 15 and end 34 and has plunger 13secured thereto substantially as shown. It will be noted that theeifective area of said piston 17 is substantially larger than that ofplunger 13 so that the total force imposed on the larger area of saidpiston will be effective as a pressure on the end of plunger 13. Thus,the unit pressure exerted by plunger 13 is considerably greater than theunit pressure exerted by piston 17.

Piston 17, on the side directed toward the cylinder end 34, is providedwith lateral passages 39, the same extending from a central bore 40.

The valve pilot 18 is connected to piston 17 and comprises a tubularmember 41 that has a nipple 42 in threaded connection with said piston.Near its outer end said tubular member 41 is provided with a pluralityof radial apertures 43a. Said valve pilot 18 is guided in a bearing 43in the bore of wall 26.

The pilot shifter valve 19 comprises a tubular member 44 that isslidingly fitted within the pilot valve 18 and is substantially longerthan the latter. The outer end of valve 19 is closed at 45 and the innerend is fitted with a valve plug 46 provided with a restriction orifice47. The hollow interior 48 of tubular member 44 is opened to the outsideof said member by plural sets of ports 49, 50, 51 and 52. Said valve isprovided with an annular outwardly directed shoulder 53 which is limitedin outward position by an inner bearing 54 provided in member 41 of thepilot valve.

The air piston actuating valve 20 comprises a tubular member 55 that hasa sliding fit in bore 27 and, with clearance, encircles the valve pilotand guide element 18. The outer cylindrical face of member 55 is reducedat 56 to form an annular passage defined by outwardly directed shoulders57 and 58. Between these shoulders, and depending on the position ofvalve 26, communication between chambers 29 and 32, and 30 and 32 is provided. Member 55, near its outer end, is provided with an internalflange 59 that slidingly seals around shifter valve 19. This flange alsoserves as one end abutment for a compression spring 60, the otherabutment being provided by a shoulder 61 in a cap 62 that closes theouter end of bore 27. Said cap is formed to have a considerableextension 63 and the same is provided with an O-ring 64 that serves toseal around valve member 44 when the latter is projected outwardly.

In the position of Pig. 1, piston 17 is retracted as is plunger 13.Spring 60 is free to urge actuating valve 20 against bearing 43 to bringthe reduced portion 56 across transverse wall so that there is directcommunication between chambers 2% and 32. Consequently, compressed airadmitted through inlet port 21 will impinge on the outer face of piston17 and project said piston toward the left to cause plunger 13 todisplace fluid past valve 65 and outward through outlet 12. As willlater be seen, there is low pressure on the left side of piston 17 atthis time and the plunger thus moves in its power stroke under the totalforce applied by the air impinging on piston 17.

As the piston 17 reaches the end of this power stroke, the apertures43a, in tubular member 41, move from the right side of bearing 43 to theleft side, as in Fig. 2. Therefore, the pressure built up in cylinderbehind piston 17 enters the interior 4% of pilot valve shifter 19through said apertures 43a and ports 50, and, from said interior d8,enters the interior of actuating valve 29 and exerts a force on flange59 of said valve that overcomes spring 6t and shifts said valve to theright, as in Fig. 2.

When said valve 29 shifts to the right, the left end 7 thereof leavesbearing 43 and opens direct communication between inlet passage 28 andchamber 29 and the interior of said valve. Thus, the pressure airentering port 21 is utilized to maintain the valve 20 shifted to its newposition. Said pressure air also enters interior 48 of valve 19 throughports 52 to exert an outward force on the closed end of valve 19 and toseep slowly through orifice 47, and through passages 39, to the leftside of piston 17. Since the recovery stroke of said piston needs merelyenough pressure air to move the mass of said piston, only a small amountof air through orifice 4? is needed.

Since actuating valve 2i), when it shifted to the right, also broughtannular spaces 30 and 32 in communication, cylinder 16, behind piston17, is vented to exhaust port 22. There is little resistance to recoverymovement of the piston. Therefore, valve 19 may strike the closed end ofcap 62 with some force. To obviate this, when said valve .19 encountersO-ring 64, the same creates a cushion of trapped air which acts as abuffer to said valve 19.

As valve 19 moves toward the right, ports 52 move past the sealed flange59 in actuating valve 20. This brings pressure air on the spring side offlange'59 and equalizes the pressure on both sides of said flange.Consequently, spring 69 is free to return the actuating valve 20 to theposition of Fig. l and the air pressure that has been applied to theleft-hand or low pressure side of the piston 17 is allowed to escapethrough vent a and the exhaust port 22, so that the cycle of operationis ready to repeat.

While the foregoing illustrates and describes what is now contemplatedto be the best mode of carrying out the invention, the construction is,of course, subject to modification without departing from the spirit andscope of the invention. it is, therefore, not desired to restrict theinvention to the particular form of construction illustrated anddescribed, but to cover all modifications that may fall within the scopeof the appended claims.

Having thus described the invention, what is claimed and desired to besecured by Letters Patent is:

1. An air-operated motor comprising an air cylinder, a valve body havingan axial bore and provided with transverse walls, to which said bore iscommon, and which divide the interior of the body into an air inletpassage, an air exhaust passage and an intermediate passage incommunication with said air cylinder, 8. piston in said cylinder andhaving passages therethrough, a sleeve valve in said bore controllingflow of air between the three mentioned passages in said body, a springnormally holding said sleeve valve in position to communicate the inletand intermediate passages, a tubular member concentric to said sleeveand connected to the piston, said member being in communication with thepassages of said piston having apertures near the end thereof remotefrom the piston, a pilot shifter valve slidably engaged in said tubularmember and said sleeve valve, said shifter valve having a hollowinterior in communication with said member and said sleeve valve throughplural sets of ports, and an orifice plug in one end of said pilotshifter valve to permit said cylinder to vent when said spring holdssaid sleeve valve in said aforesaid position.

2. A motor according to claim 1: an internal flange on the sleeve valvein sliding and sealing engagement with the shifter valve, said springengaging said flange to hold the sleeve valve in said aforesaidposition.

3. A motor according to claim 1: an internal flange on the sleeve valvein sliding and sealing engagement with the shifter valve, said springengaging said flange' to hold the sleeve valve in said aforesaidposition, and at least one set of the ports in the shifter valve beingmovable from a position on one side of said flange to a position on theother side of said flange.

4. A motor according to claim 1: said body being provided with a capclosing the end of the mentioned bore, and said shifter valve beingelongated so that one end is adapted to engage the cap, a sealing ringwithin the cap engaging said end to form a movement-arresting aircushion between the cap and the valve end.

5. A motor according to claim 1: a bearing mounted in said body adjacentto said cylinder, said tubular memher being slidable in said bearing,and the apertures in said member being movable from a position on oneside of said bearing to a position on the other side'of said bearing.

6. A motor according to claim 1: a bearing mounted in the body walladjacent said air cylinder, said tubular member being slidable in saidbearing, and said sleeve valve held against said bearing by said springto communicate the inlet and intermediate passages.

7. An air-operated motor comprising an air cylinder,

*a valve body having an axial bore enclosing one end of said cylinder,said body having an air inlet port and an exhaust port and a pluralityof transverse walls dividing said body into an air inlet passage and anair outlet passage and an intermediate passage, said walls provided witha longitudinal bore co-axial with the axis of said cylinder, a sleevevalve slidable within said bore and controlling the flow of air throughthe three mentioned passages, a bearing mounted in the body walladjacentsaid cylinder, a cap mounted in the body wall farthest away from saidcylinder and enclosing said bore, a spring biased between said sleevevalve and said cap to hold said sleeve against said bearing, said sleevewhen held by said spring permitting air pressure to pass from said inletpassage to said intermediate passage, a piston within said cylindermovable on application of air pressure through said intermediatepassage, a tubular member connected to said piston and slidably engagedwith said bearing, said member having apertures in one end that movefrom a position on one side of said bearing to a.

position on the other side of said bearing when said piston exerts apower stroke, an elongated shifter valve slidably mounted at one endwithin said member and at the other end within said sleeve, said shiftervalve being hollow and having ports to permit air pressure within saidcylinder to escape throughsaid apertures and through said hollowportion, said escaping air moving said sleeve valve against said springto permit the remaining air pressure within said cylinder to ventthrough said intermediate and outlet passages.

8; A motor according to claim 7: said pistons having passages therein.communicating the. low pressure side 6 thereof with the tubular member,and an orifice plug References Cited in the file of this patent mountedin the end of Said shifter valye said mem- UNITED ST P her to permit airpressure from said cylinder to pass 641,132 Moore Jan- 1900 through saidapertures and said ports in said shifter valve through said orifice topressurize the low pressure side 5 of said piston.

